Photo: Prasad Gori/Hindustan Times
Photo: Prasad Gori/Hindustan Times

Drinkable book seeks to turn a page in fight for clean water

Each page of The Drinkable Book is impregnated with bacteria-killing metal nanoparticles that purify water

Boston: Scientists have developed an inexpensive ‘drinkable book’ with bacteria-killing metal nanoparticles to clean contaminated water, with its pull-out pages able to filter drinking supply for four years.

While studying the material properties of paper as a graduate student, Theresa Dankovich developed an inexpensive, simple and easily transportable nanotechnology-based method to purify drinking water. She calls it The Drinkable Book, and each page is impregnated with bacteria-killing metal nanoparticles.

Although silver and similar metals have been known for centuries to have the ability to kill bacteria, no one had put them into paper to purify drinking water, Dankovich noted.

While earning her doctorate at McGill University, she found that sheets of thick filter paper embedded with silver nanoparticles could do just that, eliminating a wide variety of microorganisms, including bacteria and some viruses. She continued her research at the University of Virginia’s Centre for Global Health in US, expanding the repertoire of embedded nanoparticles to include ones made of inexpensive copper.

Dankovich also began field investigations of water purification applications in Limpopo, South Africa, as well as northern Ghana, Haiti and Kenya.

“In Africa, we wanted to see if the filters would work on ‘real water,’ not water purposely contaminated in the lab," she said. “One day, while we were filtering lightly contaminated water from an irrigation canal, nearby workers directed us to a ditch next to an elementary school, where raw sewage had been dumped. We found millions of bacteria; it was a challenging sample," she said.

“But even with highly contaminated water sources like that one, we can achieve 99.9% per cent purity with our silver- and copper-nanoparticle paper, bringing bacteria levels comparable to those of US drinking water," Dankovich added.

“Some silver and copper will leach from the nanoparticle-coated paper, but the amount lost into the water is within minimal values and well below Environmental Protection Agency and World Health Organisation drinking water limits for metals," she said.

Last year, she formed a nonprofit company, pAge Drinking Paper. In collaboration with the nonprofit WATERisLIFE organisation, her company developed the product that is essentially a book comprised of pages embedded with silver nanoparticles. Printed on each page is information on water safety both in English and the language spoken by those living where the filter is to be used. Each page can be removed from the book and slid into a special holding device in which water is poured through and filtered.

A page can clean up to 100 litres of drinking water; a book can filter one person’s water needs for four years.

Now a postdoctoral researcher at Carnegie Mellon University in US, Dankovich is further developing the technology and conducting more field studies in rural communities.

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